The present invention relates to a LED, especially to a multidirectional light scattering LED and a manufacturing method thereof that uses a scattering layer to cause output light to become scattering in multi-directions.
Since Light-emitting gallium nitride-based III-V group compound semiconductor devices are available on market at 1995, the manufacturing efficiency and yield rate are improved year after year. However, light output from LED is non-directional.
Refer to Taiwanese patent application No. 546452, applied on May 3, 2001, a LED illuminative device is disclosed. The device features on that a plurality of LED chips is disposed on surface of an insulated sphere. The LED chips are connected in series and wires are disposed on conductive parts of two ends. Transparent or translucent resin for package covers on the LED chips and part of the wires. The resin is mixed with powder of light scattering materials such as aluminum, gold, tungsten, titanium, or molybdenum.
Refer to FIG. 1, Taiwanese patent No. 229949, applied on Jan. 19, 2004, a light emitting diode and a manufacturing process thereof is disclosed. A light emitting diode includes a substrate 11′, a n-type semiconductor layer 12′, a light emitting layer 13′, a p-type semiconductor layer 14′, a transparent conductive layer 15′, a n-type electrode 16′ and a p-type electrode 17′. The transparent conductive layer 15′ has a plurality of concave holes jogged inwards the surface of the epitaxy so as to increase brightness of the LED due to scattering of the light passed through the concave holes.
Furthermore, refer to FIG. 2, Taiwanese patent No. 221036, applied on Jun. 26, 2003, a light emitting diode and a manufacturing method thereof is disclosed. A light emitting diode includes a substrate 11′, a mixing layer 18′ with a rough layer for diffusing incident light disposed over the substrate 11′, a n-type semiconductor layer 12′ over the mixing layer 18′, a light emitting layer 13′ over the n-type semiconductor layer 12, and a p-type semiconductor layer 14′ formed over the light emitting layer 13′. By the mixing layer 18′, the incident light is diffused.
Therefore, it is learned that light output from LED only in single direction is an important issue to be solved.